1. Field of the Invention
The present invention relates to a light emitting diode (LED) and a method of fabricating the same, and more particularly, to a light emitting diode having a GaN substrate and a method of fabricating the same.
2. Discussion of Related Art
Generally, a light emitting diode can be formed by growing GaN-based semiconductor layers on a sapphire substrate. However, since the sapphire substrate and GaN layers have large differences in their coefficients of thermal expansion and lattice constants, the GaN layers grown on the sapphire substrate tend to contain many crystal defects such as threading dislocations, and the like. These crystal defects can make it difficult to improve electrical and optical properties of the light emitting diode.
Furthermore, since the sapphire substrate is an electrically insulating material, the resulting light emitting diode has a lateral structure in which electrodes are disposed above the substrate. The light emitting diode of the lateral structure tends to suffer from considerable area loss due to elimination of some portions of an active area for forming electrodes, and substantial light loss caused by the electrodes. On the other hand, a flip-chip type light emitting diode is used or can be used to overcome these problems of the light emitting diode having the lateral structure. The flip-chip type light emitting diode emits light through a substrate, to reduce light loss caused by electrodes. However, the flip-chip type light emitting diode also tend to require elimination of some portions of the active area for forming electrodes, that tend to cause area loss.